Treatment of wool with nu-chlorine compounds



- perature.

Patented Mar. 25, 1952 TREATMENT OF WOOL WITH N-CHLORINE COMPOUNDS Christopher Earland, John Leggett Bailey, and Dick Carter, Leicester, England,'assignors to Wolsey Limited, Leicester, England, a British company No Drawing. Application June 5, 1948, Serial No. 31,408. In Great Britain June 24, 1947 9 Claims. (01. s-127.s)

This invention relates to the treatment of W materials consisting wholly or partly of wool" at any suitable stage from the raw material to the finished products such as yarns, fabrics, garments and the like, an object of the invention being the reduction of the normal tendency of the materials to shrink.

The form of shrinkage referred to is that which is commonly described as felting and is accompanied by a progressive closing together and thickening of the material with an accompanying loss ofarea when alternate compression and relaxation is applied to the material under conditions similar to those which exist in household washing or in a laundering machine. It does not apply to a particular form of shrinkage commonly described as relaxation which iscaused by the release of mechanical stresses when for the first time a material is immersed in water.

It is well known that solutions of chlorine and bromine in water as well as the hypohalous acids react with wool and render the latter resistant to felting. Using these reagents, the best wool products are obtained by working on the acid side of neutrality but the reaction with all these reagents is extremely rapid, even at room tem- Under the conditions usually employed, these substances largely react in less than five minutes. This very fast reaction invariably leads to uneven treatment when working in X R.S ozN and water soluble salts thereof wherein R is a hydroxyl, alkyl, alicyclic or aryl radical and X is hydrogen or chlorine.

Other processes for treating wool with various N-halogenated organic compounds inter alia for .the purpose of chlorinating the wool have been described in United Kingdom specification ,No. 482,656, U. S. A. specification No. 1,892,548 and German specifications Nos. 563,387, 647,566 and 656,112. We have examined the action of -N- halogenated organic compounds and chloramines and bromamines on wool and have found that chloramines and bromamines of the general formula RNClz and RNHCI where Ris a hydroxyl,

alkyl, alicyclic, aryl or amine or substituted amine radicals, are not suitable as shrink-proof- --ing agents. Firstly, they are not particularly effective as shrink-proofing agents and also they produce intense yellowing of the wool. This fact has been recorded in the literature (Melliand --Textilberichte 1944, p. 55) and U. S. A. specification No. 2,144,824 states that ammonia, when added to hypochlorite baths, produces yellowing. ,Ammonia and hypochlorites are known to react to form chloramines. We have found that the most useful compounds for rendering wool unshrinkable in a controllable manner are chloramides and chlor'sulphonamides of the general formulae:

R-CO

NCl

ROONHCl and ' RSOzNHCl (where R has the meaning given above) and those dichloramides and dichlorsulphonamides which do not hydrolyse to chloramines. Thus, NzN' dichlorureais not satisfactory because it tends to hydrolyse to chloramines, whereas N-dichlor toluene sulphonamide and NN dichlorbiuret are satisfactory.

Now usually from 2 /2% to 4% of available chlorine (calculated on the weight of the wool) applied from an acid aqueous solution is sufficient to render wool completely unshrinkable. Now, however, using the chlorine compounds mentioned above, more than twice as much chlorine is needed to give good unshrinkability (cf. United Kingdom specification No. 595,518). This also applies to monochlorurea (cf. Example 1 below) where between 6 to 8% of chlorine in an acid bath are needed to produce unshrinkability.

We have discovered that if the treatment of the wool is carried out in a bath containing chloample 2 below) chloride ions available.

ride ions then much smaller proportions of organic chlorine compounds are needed (only 2 to 4% of available chlorine) to render the wool unshrinkable. This is very advantageous as the wool is not oxidised so much and consequently less modified and damaged. As well as a high concentration of chloride ions, it is necessary to work in an acid solution of less than pH 2.

Accordingly the present invention provides a process for reducing the tendency of textile materials consisting wholly or partly of wool to shrink wherein textile material consisting wholly or partly of wool is immersed in an aqueous solution containing one or more chloramides or chlorsulphonamides which do not tend to yield chloramines in cold acid solutions and having a pH not greater than 2 and a chloride ion con centration greater than 0.3 N.

The chloride concentration and hydrogen ion concentration in the bath necessary to produce unshrinkability are related and it is possible to increase one and decrease the other (see EX- It is never possible to work at a pH higher than 2 (see Example 4 below). A1- so, it is of course, undesirable to work at acidities of strong acid (e. g. sulphuric acid, hydrochloric acid or phosphoric acid) of greater than N/2 since the wool is then exposed to hydrolysis. N/2 sulphuric acid and monochlorurea a 5% solution of sodium chloride is necessary to produce unshrinkability. Also, as the liquor ratio of solution volume to weight of wool becomes less the proportion of chloride in solution must be increased (see Example 3 below). Any electrolyte giving chloride ions can achieve the desired result (e. g. calcium chloride, magnesium chloride and potassium chloride) but, of course, sodium chloride is usually the cheapest source of Salts other than chlorides (e. g. sulphates, phosphates, fluorides) have no effect and if a bromide or iodide is added it is oxidised to bromine or iodine preferentially before the wool is oxidised.

Examples of acids which may be used are sulphuric acid, phosphoric acid, nitric acid and hydrochloric acid when possible hydrochloric acid is employed since it contributes both hydrogen and chloride ions so that no or less additional chloride need be employed when hydrochloric acid is the acid.

Under these conditions, the rate of reaction of the organic chlorine compound with wool is at least five times slower than when a solution of chlorine or bromine in water are used. Thus, with the N-chlor substances employed according to the present invention the reaction can be carried out at an elevated temperature (e. g. 40 C.). Good penetration is achieved whilst still being slow enough to react evenly under industrial conditions.

It is not necessary to isolate the N-chloro compound although this can usually be done. It is equally effective to mix in the actual bath the amide andhypochlorite or chlorine as the reaction:

proceeds very rapidly and completely. After a reaction with the chloramide the amide. is 9 30- However, even when working with duced again and a standing bath of reagents can be used (see Example 5 below) of acid, salt and amide and hypochlorite and acid is added to regenerate after each treatment.

The following examples illustrate how the process of the invention may be carried into effect and the advantages thereof. In the example all shrinkage figures quoted were obtained by placing the wool fabric for 1 hours in a soap solution in a household washing machine. An untreated sample shrank 25% in area in this test.

Per cent 012 on wt. of wool NaCl g./l00 ml. soln. 3 4 6 8 Per cent shrinkage after treatment 0 20 17 4 6 3 13 10 3 2 5 l0 l0 2 l 10 3 2. 5 2 0 1 The N-mono-ehlorurea was prepared by making a paste of 8 g. of urea in 2 m1. of water and passing in chlorine gas till a weight increase of2to 2.5 g. was obtained. The whole being kept at or below room temperature. The resulting solution was diluted to cos. and was stable for weeks at 0 C. The available chlorine was determined by oxidising potassium iodide and titrating the iodine liberated with sodium thiosulphate.

Example 2 The process was carried out as in Example 1 except that the content of reactive chlorine was kept constant at 4% calculated on the weight of the wool and the NaCl and H2SO4 concentrations were varied.

g. H 804 (cone) per ml.

NaC1g./100 ml. 0.25 1 2 Per cent shrinkage after treatment HHP- COQOQU) r-nmucm u H occuoooo Example 3 (a) If in Example 1 a liquor ratio of 40:1 is used (i. e. 880 ml. of water), complete unshrinkability is obtained in a 5% solution of NaCl using 3% of active chlorine calculated on the weight of the wool.

(b) Using a liquor ratio of 75:1 (i. e. 1650 ml. of water) complete unshrinkability is obtained with 2.5% of active chlorine calculated on the weight of the wool in a 5% solution of NaCl.

In both cases the time for half the available chlorine to react was about 12 mins. and no detestable amount could be iound after one hour.

Example 4 Example 3 (b) was repeated but instead of sulphuric acid varying constituents of glacial acetic acid were used.

Percent shrinkage A bath of the following composition was made Water 400 ml. (at 40 0.) Cone. HCI 4 ml.

Urea 0.4 g.

NaCl 40 g.

To it was added 2 ml. of sodium hypochlorite solution containing 0.25 g. of available chlorine. The hypochlorite immediately reacted with the urea to give N mono-chlorurea since a small sample of the solution did not give an immediate reaction with phenol; hypochlorite in acid solution reacts with phenol immediately.

5 g. of all wool knitted fabric was introduced into the bath and left in for 40 minutes.

After this the wool was withdrawn, scoured and tested. An addition to the bath of 1 ml. of HCl and 2 ml. of NaOCl was made and a further 5 g. sample of wool allowed to react for 40 minutes. This was repeated four times.

Shrinkage of wool sample:

Per cent 1st sample 1.8 2nd sample 1.4 3rd sample 2.2 4th sample 2.8

Example 6 100 lbs. of all wool knitted fabric was immersed in a solution of 400 imperial gals. of water, 4 cwt. of sodium chloride and 2 imperial gals. of 30% hydrochloric acid and 10% pints (equivalent to 2 lbs. available chlorine) of chlorurea solution (prepared as in Example 1 except that it was not diluted). The solution was at 40 C. Half the chlorine had reacted in 12 minutes and no more could be detected after 45 minutes. The wool fabric was removed from the bath, rinsed thoroughly in warm water so as to free it from salt, and then lightly scoured in soap and ammonia. The fabric was perfectly white, soft to.

the feel, with its wearing properties unimpaired. It shrank on washing 2% in area.

Example 7 V All wool knitted fabric g 5 Volume of water m1 400 Temperature C 75 Chloramide g 1 0.18

Corresponding to 2.5% of chlorine calculated on the weight of the wool.

The acid and salt concentration were varied as shown below.

Time of treatment1 hour.

(1) 10 m1. of glacial acetic acid added. No appreciable exhaustion after 1 hour. Wool shrank as much as control (22%).

(2) 10 ml. of glacial acetic acid plus 40 g. of sodium chloride. No reaction after one hour. Shrinkage 21%.

(3) 2 ml. conc. H2804; after 1 hour 50% of the original chlorine had still not reacted. Shrinkage 19%.

(4) 2 ml. conc. H2804; 40 g. of sodium chloride added; half the chlorine had gone in 20 mins.

80% had gone after one hour. The wool shrank 6%.

(5) Added 10 ml. of conc. HCl; 80% of the available chlorine reacted in one hour; shrinkage 7.1%.

Thus. the conditions for rendering wool unshrinkable are the same as for N-mono-chlorurea, except that the reaction is even slower and a useful working temperature is C.

In the absence of chloride ions, N-chlor-acetamide does not react with wool. N-mono-chlorurea still reacts under these conditions but does not render wool unshrinkable.

Example 8 N-chlorsuccinimide C Hz" 0 O NCl Hr-C O was prepared according to the method of Berichte 34, p. 4213.

Wool g 5 Water ml 400 Temperature C 75 Time of treatment 1 hour.

Example 9 N.N-dichlorbiuret N-chlorsuccinimide CONHOI NH\ CONHCI Wool ..g 5

Solution ml 400 N.N'-dichlorbiuret --g 0.35

react age 20 ml. of cone. HO]

com

5 ml. of cone. HCl 20 ml. of glacial acetic acid..

No exhaustion.

5 ml. of conc. H SOi 60 45 mins The woolwas perfectly white after all treatments except those with less than 10 ml. of HCl when it was distinctly yellowed.

Example 10 Chloramine T (pCH3.CsH4SOzNClNa).

The sample used contained 24% of available chlorine (theoretical 31%).

Wool g 5 Chloramine T g 0.6

H20 ml 400 Time of treatment 1 hour.

Temperature C 40 Time for Added acid and salt g 35531 act. ago

1 ml. of cone. HCl-HO g. NaCl 8 5 1 ml. of cone. H:S04+40 g. of N aCl 4 1 ml. of cone. HzSOi 12 14 Example 11 Chlorsulphamic acid, Cl.NH.SO2.OH.

Preparation-4.8 g. of sulphamic acid were dissolved in a mixture of 45 ml. of water and 10 ml. of glacial acetic acid cooled to 0 C. To the mixture was added 22 cos. of sodium hypochlorite solution containing 0.17 g. of available chlorine per ml. The solution turned yellow due to the liberation of 01 but was colourless after 20' mins. showing that the chloramide had formed. The

' formation of the chlorine compound from hypochlorite is slower in this case than with urea, acetamide, succinimide and biuret where the reaction is instantaneous.

Wool g Water ml 400 Temperature C 40 Reaction time 1 hour.

3.0% of available chlorine calculated on the weight of the wool.

Results similar to those obtained in the above examples can be obtained by using instead of wool a fabric consisting of wool and another textile fibre, for example union fabrics of wool and cotton or wool and silk or rayon.

' We claim:

1. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing a chlorine compound selected from the group consisting of chloramides and chlorsulphonamides which do not tend to yield chloramines in cold acid solutions, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

2. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing N-mono-chlorurea, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

3. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing sodium para-toluene sulphochloramide, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

4. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing N-chloracetamide, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

5. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing hydrochloric acid and a chlorine compound selected from the group consisting of chloramides and chlorsulphonamides which do not tend to yield chloramines in cold acid solutions, said aqueous solution having a pH not greater than 2 and a chloride'ion concentration greater than 0.3 N.

6. A process for reducing the tendency of textile materials consisting at least partly of wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution containing sodium chloride and a chlorine compound selected from the group consisting of chloramides and chlorsulphonamides which do not tend to yield chlora-mines in cold acid solutions, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

'7. A process for reducing the tendency of textile materials consisting at least partly of Wool to shrink, which comprises immersing a textile material consisting at least partly of wool in an aqueous solution prepared by mixing together in water an amide and a substance selected from the group consisting of a hypochlorite and chlorine, said aqueous solution having a pH not greatamide and a substance selected from the group consisting of a hypochlorite and chlorine, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

9. A process for reducing the tendency of textile materials consisting at least partly of Wool to shrink, which comprises immersing a textile material consisting at least partly of Wool in an aqueous solution prepared by mixing together in an aqueous solution of sodium chloride an amide and a substance selected from the group consisting of a hypochlorite and chlorine, said aqueous solution having a pH not greater than 2 and a chloride ion concentration greater than 0.3 N.

CHRISTOPHER EARLAND. JOHN LEGGETT BAILEY. DICK CARTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,892,548 Feibelmann Dec. 27, 1932 Number Name Date 2,144,824 Wiegand Jan. 24, 1939 2,414,704 Ward Jan. 21, 1947 2,429,082 Stevenson Oct. 14, 1947 FOREIGN PATENTS Number Country Date 118,721 Australia July 18, 1944 549,362 Great Britain Nov. 18, 1942- 647,566 Germany July 7, 1937 OTHER REFERENCES Hirst et al.: some Experiments on Chlorination of Wool. Journal of the Textile Institute,

volume 24, January to June 1933, pages T174 to T184. (Journal in Patent Ofiice Scientific Library.)

Wilson: The Chemistry of Leather Manufacture. Second ed., volume 1, Chemical Catalog Company, New York, 1928, pages 121 to 124, 146.

Heermann: Enzyklopadie der Textilchemischen Technologie, Julius Springer, Berlin, 1930-, pages 140 and 141. 

1. A PROCESS FOR REDUCING THE TENDENCY OF TEXTILE MATERIALS CONSISTING AT LEAST PARTLY OF WOOL TO SHRINK, WHICH COMPRISES IMMERSING A TEXTILE MATERIAL CONSISTING AT LEAST PARTLY OF WOOL IN AN AQUEOUS SOLUTION CONTAINING A CHLORINE COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHLORAMIDES AND CHLORSULPHONAMIDES WHICH DO NOT TEND TO YIELD CHLORAMINES IN COLD ACID SOLUTIONS, SAID AQUEOUS SOLTUION HAVING A PH NOT GREATER THAN 2 AND A CHLORIDE ION CONCENTRATION GREATER THAN 0.3 N. 